1. Field of the Invention
The present invention relates to a light emitting device, and more particularly to a light emitting device that can be utilized in laser displays, projector devices, endoscopes, and so forth.
2. Background Information
With laser displays, projector devices, endoscopes, and so forth, light of various wavelengths is combined to produce light of the desired wavelength (see Japanese Laid-Open Patent Application 2005-205195, for example), and this requires a light emitting device that is capable of emitting the blue, red, green, or other light that is to be combined.
For example, there is a projector device comprising a semiconductor laser (as a solid-state light source that emits blue light with a wavelength of 405 nm), an optical fiber having a core doped with a wavelength downward conversion material for converting excitation light to blue, an optical fiber having a core doped with a wavelength downward conversion material for converting excitation light to green, an optical fiber having a core doped with a wavelength downward conversion material for converting excitation light to red, a converging lens and a projection lens for guiding the light emitted from the optical fibers to a liquid crystal panel, and the liquid crystal panel, wherein the liquid crystal panel performs processing in which the desired image is displayed on a screen by using the red, blue, and green light emitted from the optical fibers, respectively (see Japanese Laid-Open Patent Application 2003-233123, for example).
With this light emitting device, the light source may in some cases be an LED, but a problem with an LED is its low brightness. Also, the light source may in some cases be an SHG laser or other such solid-state laser or a gas laser, but because these entail a complicated structure, the light emitting device becomes large and power consumption goes up.
It is therefore believed to be preferable for the light source to be a laser diode, but so far no laser diode that emits green light has been developed (there are laser diodes that emit a green component, but green does not result from color mixing). Thus, when the light source consists of a laser diode, it is necessary to obtain green from a laser diode that emits light of another color besides green.
Also, it will be necessary in the future to further increase the luminous flux emitted from a light emitting device, but at the present time the luminous flux of emitted light is not large enough to meet future needs.